Research Progress on the Application of Human Oral Microbiome in Forensic Individual Identification / 法医学杂志

The oral cavity is the second largest microbial bank in humans after the intestinal canal, colonizing a large number of microorganisms including viruses, bacteria, archaea, fungi and protozoa. The great number of microbial cells, good DNA stability, and individual has a unique microbial community, these characteristics make the human microbiome expected to become a new biomarker for forensic individual identification. This article describes the characteristics of human oral microorganisms and microbial molecular markers in detail, analyzes the potential application value of microorganisms in forensic individual identification, and reviews the research progress of human oral microorganisms in forensic individual identification.

Analysis and application of haplotype in forensic medicine / 法医学杂志

Haplotype is a lineable combination of alleles at multiple loci that are transmitted together on chromosome or mitochondrion. In October 2002, the international HapMap project started and aimed at mapping the haplotype blocks of human being and discovering the Tag SNPs by determining the DNA sequence variation patterns, variation frequency and their relationship. This review summarizes the formation and distribution of the haplotype and the current three haplotype-analysis methods including the methodology of experiment, the deduction from pedigrees and the statistic method. When an allele linkage disequilibrium occurs, the genetic probability would be evaluated by haplotype. The importance of haplotype has been recognized and its application has been gradually increased in forensic sciences. The current focus on haplotype study in forensic science involves Chromosome Y, Mitochondrial DNA and Chromosome X, which are useful supplements of genetic marks.

Multiple amplification of 16S rRNA gene and Cytb gene in mitochondrial DNA for species identification / 法医学杂志

OBJECTIVE@#To establish a fluorescent multiple amplification system of 16S rRNA and Cytb genes located in mitochondrial DNA for species identification.@*METHODS@#A pair of primers of 16S rRNA gene and Cytb gene of the mitochondrial DNA was designed with the software Primer 5.0 to construct a multiple amplification system. The amplified products from human and five species of animals, including cattle, pig, dog, chicken and grass carp were analyzed by 310 Genetic Analyzer.@*RESULTS@#The amplified products of these samples showed two peaks. The common one was 358bp and the specific one different in unique species was between 231bp and 256bp.@*CONCLUSION@#The multiplex amplification system can exactly distinguish the species of human from five common animals.

A study of paternity testing with considering mutation / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To formulate recommendations in the evaluation of results of genetic analyses in paternity testing under considering mutations.</p><p><b>METHODS</b>A total of 15 short tandem repeat(STR) loci were employed for this study, which were included CSF1PO, FGA, TH01, TPOX, VWA, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D21S11, PentaD and PentaE. Both 100 cases of true trio and 100 cases of false trio were investigated.</p><p><b>RESULTS</b>The numbers of mismatch alleles in different STR loci were observed in 100 cases of false trio. The different distributions of paternity index were obtained, including the changes of paternity index in each case of true trio under simulated mutations.</p><p><b>CONCLUSION</b>In order to avoid the effect of mutations, the exclusion of paternity was never considered on the basis of a single locus. The threshold values of the combined probability of exclusion and the paternity index were important for both exclusion and inclusion of paternity. The scientific evidence for paternity testing can be obtained when both the combined probability of exclusion and the paternity index meet the threshold values. However, when either the combined probability of exclusion or the paternity index can not meet the threshold values, more genetic markers should be added.</p>

Computer-aided molecular modeling and activity estimation for ligand screening with specific phage clone as the target / 南方医科大学学报

To investigate the interaction between tumor necrosis factor alpha (TNF alpha) mimotopes and TNF alpha-binding peptides screened from random phage display peptide library with TNF alpha mimotopes displayed on phage clone as the target, the computational docking program AutoDock (with confirmation calculations using Discover) was used to predict and analyze the binding modes of LLT-18 (TNF alpha binding peptide, sequence EHMALTYPFRPP) with TNF alpha, after which LCS-7 (TNF alpha mimic phage clone, displayed positive sequence c-RRPAQSG-c) was docked to LLT-18 manually. The binding between LLT-18 and TNF alpha or LCS-7 was stabilized predominantly through electrostatic interaction and H-bond formation. The Arg residues in TNF alpha or LCS-7 were important for their interaction with LLT-18. For LLT-18, the key amino acid residues were Glu1, His2, Met3 and Tyr7. These results suggest the feasibility of screening ligand to single epitope with specific phage clone as the target, and of predicting the interaction between small peptides by computer-aided molecular modeling.

Polymorphism of five short tandem repeat systems in Chinese Han population in Chengdu / 法医学杂志

OBJECTIVE@#To obtain population genetic data of loci D11S4951, D11S4957, GATA193H05, D2S2951, and D6S2421 in Han population in Chengdu area and to validate the value of their forensic application.@*METHODS@#Blood samples were collected in EDTA tubes from unrelated individuals. DNAs were extracted with Chelex-100 and were analyzed by PCR and horizontal PAGE followed by silver staining.@*RESULTS@#Alleles 7, 10, 8, 6 and 8 were found in 5 STR loci, respectively. No deviations from Hardy-Weinberg balance were observed. The heterozygosities observed were 0.743, 0.772, 0.833, 0.650 and 0.800, respectively. The chances of exclusion were 0.497, 0.549, 0.662, 0.356 and 0.599, and the discrimination powers were 0.863, 0.912, 0.947, 0.829 and 0.931.@*CONCLUSION@#All of the five loci studied may be useful markers for individual identification and paternity testing.

Screening of short peptides binding to cell surface interleukin-2 receptor alpha chain / 南方医科大学学报

<p><b>OBJECTIVE</b>To screen and characterize the short peptides which bind specifically to interleukin-2 (IL-2) receptor alpha chain (IL-2Ralpha) for acquisition of small antagonists for blocking the binding of IL-2 with IL-2Ralpha.</p><p><b>METHODS</b>12-mer phage displayed peptide library was screened with the target cells of MT-2 cells which expressed IL-2Ralpha at high levels. The binding phage clones were eluted by anti-IL-2Ralpha monoclonal antibody. After 3 rounds of screening, the positive phage clones were identified by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry, and the amino acid sequences of the positive clones were deduced from the DNA sequences.</p><p><b>RESULTS</b>Seven positive clones were screened out of the 17 phage clones bound to MT-2 cells. The positive clone M15 could bind specifically to MT-2 cell and PHA-activated peripheral blood monouclear cells. Amino acid sequence analysis identified 6 sequences, all of which contained hydrophilic residues, and 5 of these 6 sequences included Tyr, Phe and Leu conservative residues.</p><p><b>CONCLUSION</b>The peptide sequences containing Tyr, Phe conservative residues identified in this study can bind to cell surface IL-2Ralpha.</p>